Vinyl group
In chemistry, vinyl or ethenyl[1] (abbreviated as Vi[2]) is the functional group with the formula H-C=CH2. It is the ethylene (IUPAC ethene) molecule (H2C=CH2) with one fewer hydrogen atom. The name is also used for any compound containing that group, namely R−CH=CH2 where R is any other group of atoms.
An industrially important example is vinyl chloride, precursor to PVC,[3] a plastic commonly known as vinyl.
Vinyl is one of the alkenyl functional groups. On a carbon skeleton, sp2-hybridized carbons or positions are often called vinylic. Allyls, acrylates and styrenics contain vinyl groups. (A styrenic crosslinker with two vinyl groups is called divinyl benzene.)
Vinyl polymers[]
Vinyl groups can polymerize with the aid of a radical initiator or a catalyst, forming vinyl polymers. Vinyl polymers contain no vinyl groups. Instead they are saturated. The following table gives some examples of vinyl polymers.
Monomer example | Example of resulting polymer |
---|---|
Vinyl chloride | Polyvinyl chloride (PVC) |
Vinyl fluoride | Polyvinyl fluoride (PVF) |
Vinyl acetate | Polyvinyl acetate (PVAc) |
Reactivity[]
Vinyl derivatives are alkenes. If activated by an adjacent group, the increased polarization of the bond gives rise to characteristic reactivity, which is termed vinylogous:
- In allyl compounds, where the next carbon is saturated but substituted once, allylic rearrangement and related reactions are observed.
- Allyl Grignard reagents (organomagnesiums) can attack with the vinyl end first.
- If next to an electron-withdrawing group, conjugate addition (Michael addition) can occur.
Vinyl organometallics, e.g. vinyllithium and vinyl tributyltin, participate in coupling reactions such as in Negishi coupling.
Etymology[]
The etymology of vinyl is the Latin vinum = "wine", and the Greek word "hylos" 'υλος (matter or material), because of its relationship with ethyl alcohol. The term "vinyl" was coined by the German chemist Hermann Kolbe in 1851.[4]
See also[]
- Acetylenic
- Allylic/Homoallylic
- Alpha-olefin
- Benzylic
- Propargylic/Homopropargylic
- Vinylogous
References[]
- ^ IUPAC Provisional Recommendations 2004 Chapter 5
- ^ Rules for abbreviation of protecting groups p.310
- ^ Endo, Kiyoshi (December 2002). "Synthesis and structure of poly(vinyl chloride)". Progress in Polymer Science. 27 (10): 2021–2054. doi:10.1016/S0079-6700(02)00066-7.
- ^ H. Kolbe (1851), "On the chemical constitution and nature of organic radicals," The Quarterly Journal of the Chemical Society of London, 3 (4) : 369-405; see footnote on page 376.
- Alkenyl groups
- Monomers
- Functional groups